DeLaGarza suffered the injury in the 30th minute of the 1-1 draw with the Colorado Rapids on Sunday during a crunching collision with Colorado forward Omar Cummings. The 24-year-old defender admitted after the match that he didn’t remember what had happened, but television replays appeared to show DeLaGarza’s inner left knee knocking with the knee of Cummings.

The injury prevented DeLaGarza from placing any weight on his left knee, requiring the training staff to carry the defender to the locker room as play resumed.

“Just pain. That’s all I can say,” DeLaGarza told LA Galaxy Insider of his condition following the match. “I don’t know what is wrong. They told me what they think is wrong, but I don’t want to jump to conclusions.”

At halftime, a team official announced that the preliminary diagnosis of DeLaGarza’s injury revealed a left knee sprain. The defender is expected to undergo a series of tests over the coming days to determine the extent of the injury.

The injury could be a serious blow as DeLaGarza—who has started 30 of 31 matches for LA this season—has played a pivotal role in LA’s defensive resurgence over the last three months.

“It’s a tough loss losing A.J. and it’s disappointing to see him go down like that,” defender Todd Dunivant said of DeLaGarza’s injury. “We’re pulling for him and hopefully for the best with his scan and we’ll see what comes of it.”

When DeLaGarza was carried off, the task of stepping into the Galaxy back four fell to rookie center back Tommy Meyer, who was making his first league start since May 5 and his first appearance alongside Omar Gonzalez. In 56 minutes of action, the first-year defender was stellar, not appearing to miss a beat as the Galaxy were able to shut down the Rapids attack.

“I have faith in him, David [Junior Lopes]. [Andrew] Boyens, Gaul. We have a deep squad,” said DeLaGarza of Meyer. “We’ll see who is going to be in there and how long we’re going to need them for.”